PROJECT SUMMARY (See instructions); This proposal is a continuation of Project 2 in the original SPORE grant. Pertinent to this proposal, we have developed an anti-DRS monoclonal antibody therapy for pancreatic cancer through in vitro studies, animal model efficacy and with an industry partner (Daiichi Sankyo), Phase I and recently completed Phase II trials in pancreatic cancer. We have also discovered a novel molecule (DDX3) which appears to play a major role in regulation of anti-DRS mediated apoptosis. In this proposal, we will explore two strategies to enhance the efficacy of anti-DRS monoclonal therapy especially in pancreatic tumor cell lines which are intermediate or resistant to anti-DRS. The two strategies are to evaluate the addition of a monoclonal anti-DR4 reagent or the addition of small molecule modulators ofthe apoptosis cascade. The two apoptosis modulators to be evaluated are AT-101, a Bcl-2 family inhibitor, and AT-406, an lAP family inhibitor. These two strategies will be studied using in vitro analysis and orthotopic and metastatic xenogeneic pancreatic cancer models leading to a Phase I trial of the best strategy. In addition, we will continue studies of DDX3 and the DRS/DDX3 complex as a putative biomarker for tumor cell sensitivity/resistance to death receptor mediated anti-tumor efficacy and as the target of enhancement strategies for anti-DR mediated anti-tumor effects.